Study on the detection and harmful effect of crude toxin produced by cucumber seedborne Fusarium species

To detect the concentration of fusaric acid in the crude toxin and its harmful effect on the seeds and seedlings,fusaric acid in the crude toxin was extracted from the cucumber seedborne Fusarium isolates with ethyl acetate and diethyl ether,and analysed using the method of high performance liquid chromatography(HPLC).The effects of the crude toxin on seed germination and seedlings were examined using the crude toxin to treat cucumber seeds and cucumber seedling roots.Results showed that fusaric acid was detected in all of the crude toxins from the seven seedborne Fusarium isolates(designed SC-CQ-P,HLJ-XC-S,LN-ZN203-S,GD-HY-S,HN-XH-S,LN-ZN6-S and HB-TS-R),and the concentrations of fusaric acid were 3 574.71,866.43,291.10,123.32,856.13,358.27 and 327.71 μg/mL respectively.The crude toxin from all the seven isolates of Fusarium spp.affected cucumber seed germination negatively and caused wilt symptoms on cucumber seedling leaves,and the toxic effect on the seedlings was enhanced with the increase of the toxin concentration and the treatment time.To our knowledge,this is the first report about production of fusaric acid by the seedborne Fusarium species in cucumber and about the negative effect of the crude toxin for the cucumber seedlings in China.